SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a452f125dd8496133ab0a3c97b7df35ed02b0e36ff474acdbc76ea976cfd413' 
  AND token = 'qktwO2KL39JReg1kNd5kYWlSyV+T7Gv5uVnmQW4Za1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}